1. Field of the Invention
The present invention relates to an ink jet printer, and a method of and an apparatus for adjusting the ink discharge velocity in the ink jet printer.
2. Description of the Related Art
In such an ink jet printer, there is equipped an actuator of an ink jet head, which expands and restores the capacity of many ink storing chambers formed inside the actuator using a piezoelectric element installed corresponding to each of the ink storing chambers, and which applies pressure to the ink inside the ink storing chamber. In this way, the actuator discharges the ink from an ink discharge hole formed in each of the ink storing chambers to the external i.e., onto the recording sheet.
The ink discharge velocity of the actuator constructed in this manner varies depending upon the diameter of the ink discharge hole, the width or length of the ink storing chamber and the variation of the characteristics of the piezoelectric element and the like.
Hence, in order to correct this variance of the ink discharge velocity, either a driving voltage (i.e., a voltage of a wave for driving the piezoelectric element) or a driving voltage waveform (i.e., a waveform of a wave for driving the piezoelectric element) for expanding and restoring the piezoelectric element is adjusted or both of the driving voltage and the driving voltage waveform are adjusted.
However, according to the above mentioned ink jet head, since the driving voltage waveform and the driving voltage influence each other, it is a very cumbersome operation to adjust both of the driving voltage and driving voltage waveform.
In addition, in a case where the variance of the ink discharge velocity is corrected by adjusting only the driving voltage, the driving voltage needs to be adjusted over a wide range. However, in order to do this, the variable range of the power source voltage needs to be set very wide correspondingly, which caused a problem in the safety and the cost thereof.